Sydney heatwave: Is it hot enough for you?

By Sarah Perkins

October 10, 2013 — 1.46pm

One of the great oddities of recent times in Australia is that during our increasingly frequent and intense fire seasons – when we're losing houses and, unfortunately, lives – it is seen by many as rude or in poor taste to talk about climate change.

It is quite a bizarre response considering an ever-growing body of research highlights that increases in heat waves, fire danger and extreme temperatures are intimately linked to global warming.

A Rural Fire Service brigade abandons a truck during a burn at Londonerry.Credit:Nick Moir

More importantly, these three areas are considered to be the earliest, most responsive and well-defined impacts of climate change.

In Australia, we have seen the Bureau of Meteorology add a new temperature colour to its maps, the creation of a catastrophic fire danger category, the hottest 12 months on record and heat records falling at increasing rates over the past 50 years. Worldwide research has shown that the number of new heat records being set has increased by 40 per cent while the number of extreme cold records being set has declined by 40 per cent.

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We are seeing a shift in the climate towards warmer conditions that will unequivocally have an impact on the timing and intensity of fires.

In Sydney, our fire season started this year in September. On Thursday we have had forecasts for a 39-degree day in Sydney and the declaration of catastrophic fire conditions in other parts of NSW.

Unfortunately, for me, this fire season shift comes as no surprise – it is exactly what is expected under climate change. We are no longer talking about projections, but observations made over the past 50 years and longer that reveal the change.

Our own research at the ARC Centre of Excellence for Climate System Science has shown that in Australia heatwaves are getting longer, hotter and more frequent. Beyond the increased fire danger, the health impacts of high overnight temperatures are enormous particularly on the more vulnerable and elderly sections of our population. Death rates go up during persistent heatwaves.

This week in the journal Nature, new research claimed to pinpoint the exact year that many of the world's major cities will see the climates completely alter. While this kind of precision is perhaps inappropriate when talking about complete transformations in regional climates, it does not alter the fact that this is where we are heading.

When we look at future climates, the preponderance of evidence suggests an increasing number of extreme heat events, no matter how they are measured. There is also increasing confidence around the idea that wet areas will get wetter and dry areas will get drier. The changes in observed salinity in our oceans supports this proposition.

Future projections of severe rainfall events under enhanced atmospheric greenhouse gas concentrations show they are also likely to be more intense.

This summer follows two intense La Nina periods that brought extensive rainfall to the east coast of Australia. While there is no clear indicator that these record rainfall events were due to climate change, because precipitation is hard to model, the extreme flooding and rainfall from these two years has created a vegetation load that that has many in our fire services deeply concerned.

On a personal note, my partner is a volunteer in the Rural Fire Service. The amount of fuel load that has built up over the last few years coupled with an early fire season is something that he and his colleagues have rarely, if at all, seen. They are expecting the worst while praying for a reprieve in the summer ahead.

Hazard reduction burning has been particularly fraught this year and both my partner and his colleagues have explicitly said they are concerned of the conditions and what the summer could bring.

At the same time, their concerns are magnified by the fact that so few people have prepared for this fire season even though it has already started. Gutters are still filled with leaves and flammable objects litter properties that are close to the verge between bush and urban areas.

It is my hope that we don't have the devastation inflicted by infernos such as those in Victoria and Tasmania visited upon NSW. With a partner who is likely to be in the frontline fighting these fires, I have real skin in the game.

But if Sydney and NSW does experience such devastation, I don't want us to ignore the role climate change played. There is no doubt in my mind that global warming is significantly contributing to making Australia's fire danger worse than it has ever been.

If towns are burning and Australian lives are being put more at risk because of this, we have a responsibility to face the role of climate change, to talk about it and to consider our response to a challenge that will only grow if we do nothing.

When lives and communities are being devastated it's more than rude not to talk about climate change and fires, it's life threatening.

Sarah Perkins is a researcher at the ARC Centre of Excellence for Climate System Science.